A method for preparing a polyketone separation membrane by low-temperature thermally induced phase separation

Abstract

The application discloses a method for preparing a polyketone separation membrane by a low-temperature thermally induced phase separation method and belongs to the technical field of organic separation membranes. A deep eutectic solvent is prepared by mixing a hydrogen bond acceptor and a hydrogen bond donor with a proper molar ratio, and the deep eutectic solvent is used as a diluent of the polyketone, mixed with the polyketone and a hydrophilic additive, and then a flat membrane and a tubular membrane are prepared by a thermally induced phase separation method. The deep eutectic solvent as the diluent significantly reduces the membrane preparation temperature, reduces the requirement for equipment and reduces energy consumption.

Description

TECHNICAL FIELD

[0001] The application relates to a method for preparing a polyketone separation membrane by a low-temperature thermal phase separation method, and belongs to the field of organic separation membranes. BACKGROUND

[0002] Aliphatic polyketone (POK) is a new green and environmentally friendly polymer, which is polymerized from carbon monoxide and olefins (ethylene and propylene), and is an excellent engineering plastic. The POK membrane has the characteristics of low cost, good hydrophilicity, good chemical resistance, high temperature resistance and good mechanical properties. The POK can only be dissolved in a small number of solvents at low temperature to prepare a separation membrane by a non-solvent induced phase separation method, such as hexafluoroisopropanol, an aqueous solution of phenols (patent CN103781832B) and an aqueous solution of metal salts (patent US7223829B2). These solvents have problems such as great toxicity, limited solubility and serious oxidation during the dissolving process.

[0003] The thermal phase separation method is a commonly used method for preparing a polyketone separation membrane, and has the characteristics of simple preparation process, wide selection range of materials and easy realization of large-scale production. However, the method has high requirements for the high-temperature resistance of the equipment itself and increases the energy consumption, and the cost of large-scale production is high. SUMMARY

[0004] In view of the deficiencies of the prior art, the application provides a method for preparing a polyketone separation membrane by a low-temperature thermal phase separation method.

[0005] Specifically, the purpose of the application can be achieved by the following technical scheme:

[0006] The deep eutectic solvent, the polyketone and the hydrophilic additive are mixed, stirred and filtered and defoamed to obtain a coating film casting solution for coating;

[0007] The coating film casting solution for coating is coated on a non-woven fabric support layer, and water bath curing is performed to obtain a polyketone separation membrane.

[0008] Optionally, the hydrogen bond acceptor comprises vanillin, the hydrogen bond donor comprises water, glycerol or ethylene glycol, and the molar ratio of the hydrogen bond donor to the hydrogen bond acceptor is 1:5-5:1.

[0009] Optionally, the polyketone is polymerized from carbon monoxide and olefins (ethylene and propylene).

[0010] Optionally, the additive is a hydrophilic additive, and comprises F-108 or F-127.

[0011] Optionally, the coating film casting solution for coating comprises the following components in parts by weight: 10-30 parts of polyketone, 1-10 parts of additive and 60-88 parts of deep eutectic solvent.

[0012] Optionally, the material of the non-woven fabric comprises PET, PP or PPS.

[0013] Advantages of the present application:

[0014] The present application uses a special deep eutectic solvent as a diluent, which can reduce the film preparation temperature to below 100℃, significantly reduce the film preparation temperature, reduce the requirement of high temperature resistance of equipment, and reduce the energy consumption. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 Surface topography map for Example 1

[0016] Figure 2 Surface topography map for Example 7 DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0018] Specific embodiments of the present application are provided below.

[0019] Example 1:

[0020] A method for preparing a polyketone separation membrane by low-temperature thermally induced phase separation, comprising the following steps:

[0021] (1) Take ethylene glycol: vanillin = 2:1 by mole ratio, and stir at 80℃ to form a deep eutectic solvent;

[0022] (2) Add 15% POK and 3% F-127 to the above-mentioned 82% deep eutectic solvent, and continuously stir at 100℃ until a uniform transparent casting solution is formed;

[0023] (3) Filter the casting solution with a stainless steel filter screen, and vacuum degas the filtrate to obtain a coating film casting solution;

[0024] (4) Use a tubular membrane integrated film forming machine to coat the coating film casting solution on the inner layer PET non-woven fabric support layer, and the outer layer is also a PET non-woven fabric. Then immerse the membrane tube in a 50℃ pure water cooling bath for solidification and molding. After molding, the membrane is immersed in pure water for 2 days, then placed in a 30wt% glycerol aqueous solution for 1 day, and then taken out for drying to obtain a dry POK tubular membrane.

[0025] Example 2:

[0026] A method for preparing a polyketone separation membrane by a low-temperature thermally induced phase separation method, comprising the following steps:

[0027] (1) Take the molar ratio of ethylene glycol: vanillin = 1:2, stir at 90°C to form a deep eutectic solvent;

[0028] (2) Add 15% POK and 3% F-127 to the above-mentioned 82% deep eutectic solvent, and continuously stir at 95°C until a uniform transparent casting solution is formed;

[0029] (2) Filter the casting solution with a stainless steel filter screen, and vacuum degas the filtrate to obtain a coating casting solution;

[0030] (3) Use a doctor blade to coat the coating casting solution on a PPS non-woven fabric support layer, then immerse the membrane in a 50°C pure water cooling bath for solidification and molding, and then immerse the molded membrane in pure water for 2 days, and then immerse it in a 30wt% glycerol aqueous solution for 1 day, and then take out the membrane for drying to obtain a dry POK flat membrane.

[0031] Example 3:

[0032] A method for preparing a polyketone separation membrane by a low-temperature thermally induced phase separation method, comprising the following steps:

[0033] (1) Take the molar ratio of water: vanillin = 2.25:1, stir at 90°C to form a deep eutectic solvent;

[0034] (2) Add 12% POK and 2% F-108 to the above-mentioned 86% deep eutectic solvent, and continuously stir at 100°C until a uniform transparent casting solution is formed;

[0035] (3) Filter the casting solution with a stainless steel filter screen, and vacuum degas the filtrate to obtain a coating casting solution;

[0036] (4) Use a tubular membrane integrated film forming machine to coat the coating casting solution on an inner layer PET non-woven fabric support layer, and the outer layer is also a PET non-woven fabric, then immerse the membrane tube in a 50°C pure water cooling bath for solidification and molding, and then immerse the molded membrane in pure water for 2 days, and then immerse it in a 30wt% glycerol aqueous solution for 1 day, and then take out the membrane for drying to obtain a dry POK tubular membrane.

[0037] Example 4:

[0038] A method for preparing a polyketone separation membrane by a low-temperature thermally induced phase separation method, comprising the following steps:

[0039] Example 3 formula remains unchanged, after coating the casting solution, immerse it in a 19°C pure water cooling bath, and other post-processing processes remain unchanged.

[0040] Example 5:

[0041] A method for preparing a polyketone separation membrane by a low-temperature thermally induced phase separation method, comprising the following steps:

[0042] (1) Take glycerol: vanillin = 1:4.4 in molar ratio, and stir at 80°C to form a deep eutectic solvent;

[0043] (2) Add 15% POK and 3% F-127 to the above-mentioned 82% deep eutectic solvent, and continuously stir at 90°C until a uniform transparent casting solution is formed;

[0044] (2) Filter the casting solution with a stainless steel filter screen, and vacuum degas the filtrate to obtain a coating casting solution;

[0045] (3) Use a tubular membrane integrated film forming machine to coat the coating casting solution on the inner layer PPS non-woven support layer, and the outer layer is also PPS non-woven, then immerse the membrane into a 30°C pure water cooling bath for solidification and molding, place the molded membrane into pure water for 2 days, then immerse it into a 30wt% glycerol aqueous solution for 1 day, take out the membrane for drying, and obtain a dry POK tubular membrane.

[0046] Example 6:

[0047] A method for preparing a polyketone separation membrane by a low-temperature thermally induced phase separation method, comprising the following steps:

[0048] The formulation of Example 5 remains unchanged, and after the casting solution is scraped, it is left in the air for 30 seconds, then immersed into a pure water cooling bath, and the other post-processing processes remain unchanged.

[0049] Example 7:

[0050] A method for preparing a polyketone separation membrane by a low-temperature thermally induced phase separation method, comprising the following steps:

[0051] (1) Take glycerol: vanillin = 1:4.4 in molar ratio, and stir at 80°C to form a deep eutectic solvent;

[0052] (2) Add 15% POK and 3% F-127 to the above-mentioned 82% deep eutectic solvent, and continuously stir at 90°C until a uniform transparent casting solution is formed;

[0053] (3) Filter the casting solution with a stainless steel filter screen, and vacuum degas the filtrate to obtain a coating casting solution;

[0054] (4) Use a tubular membrane integrated film forming machine to coat the coating casting solution on the inner layer PPS non-woven support layer, and the outer layer is also PPS non-woven, then immerse the membrane into a 30°C pure water cooling bath for solidification and molding, place the molded membrane into pure water for 2 days, then immerse it into a 30wt% glycerol aqueous solution for 1 day, take out the membrane for drying, and obtain a dry POK tubular membrane.

[0055] Comparative Example 1:

[0056] (1) Respectively take 22% POK, 3% F-127, 75% dimethyl sulfoxide diluent, 160℃ stirring, until a uniform transparent casting solution is formed;

[0057] (2) The casting solution is filtered with a stainless steel filter screen, and the filtrate is vacuum degassed to obtain a coating film casting solution;

[0058] (3) The coating film casting solution is coated on the PP non-woven fabric support layer with a doctor blade, then the film is immersed in a 40℃ pure water cooling bath for solidification and molding, the molded film is immersed in pure water for 2 days, then placed in a 30wt% glycerol aqueous solution for 1 day, the film is taken out for drying to obtain a dry POK flat film.

[0059] The above examples and comparative examples were tested for pure water flux at a temperature of 25℃ and a pressure of 0.1MPa, ethanol was used as the wetting liquid, and the average pore size was tested by a bubble point method pore size analyzer, as shown in Table 1.

[0060] Case No. Pure water flux (L / m 2 • h) Average pore diameter (nm) Mixing agitation temperature (°C) Example 1 741 400 100 Example 2 280 90 95 Example 3 148 46 100 Example 4 555 190 100 Example 5 462 175 90 Example 6 1757 286 90 Example 7 540 150 95 Comparative Example 1 630 125 160

[0061] From the results of the above examples and comparative examples, it can be seen that:

[0062] The temperature used in the preparation of the polyketone separation membrane by mixing and stirring with the deep eutectic solvent is significantly lower than that in the comparative examples, greatly reducing the high temperature resistance requirement of the equipment and also reducing energy consumption.

[0063] The above examples have described the technical solutions and beneficial effects of the present application in detail, it should be understood that the above description is only a specific embodiment of the present application, and is not intended to limit the present application. Any modification, supplement and equivalent replacement within the principle range of the present application shall be included in the protection scope of the present application.

Claims

1. A method for producing a polyketone separation membrane, characterized by, The method comprises the following steps: The hydrogen bond acceptor includes vanillin, and the hydrogen bond donor includes water, glycerol or ethylene glycol; The deep eutectic solvent is mixed with polyketone and a hydrophilic additive, stirred, filtered and defoamed to obtain a casting solution for film coating, wherein the deep eutectic solvent serves as a diluent; The casting solution for film coating is applied to a non-woven fabric support layer, and water bath solidification is performed to obtain a polyketone separation membrane.

2. The method of claim 1, wherein, The molar ratio of the hydrogen bond donor to the hydrogen bond acceptor in the deep eutectic solvent is 1:5-5:

1.

3. The method of claim 1, wherein, The polyketone is polymerized from carbon monoxide and olefins.

4. The method of claim 1, wherein, The hydrophilic additive includes F-108 or F-127.

5. The method of claim 1, wherein, The weight ratio of the polyketone, the hydrophilic additive and the deep eutectic solvent in the casting solution for film coating is 10-30:1-10:60-88.

6. The method of claim 1, wherein, The material of the non-woven fabric includes PET, PP or PPS.

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